Simplified Wave Energy Device Without One-way Clutches

ABSTRACT

This invention is a greatly simplified device for transforming the energy of water waves into useable energy. The invention is a device for transforming the energy of water waves into useable energy comprising two or more buoys or buoys, and structural members connecting buoys, whereby motions of buoys relative to one another generates torque, and a means for transferring torque to one or more generators, and a means by which to enable all generator currents to flow in a single beneficial direction. Novel systems for interconnecting such devices are also described herein.

CROSS-REFERENCES TO MOST RELATED APPLICATIONS

Patent or Application # Title 12/175,196 Energy Transformation Device7,199,481 Wave energy conversion system 6,857,266 Wave energy converter6,812,588 Wave energy converter 6,772,592 Float dependent wave energydevice 6,791,205 Reciprocating generator wave power buoy 6,765,307 Waveenergy converter (WEC) 6,392,314 Wave energy converter 6,226,989 Waveenergy converter 5,027,000 Method and apparatus for generatingelectricity using wave energy 4,412,417 Wave energy converter 4,359,868Ocean wave energy converter 4,345,434 Sea and ocean wave energyconverter 4,258,269 Wave power generator 4,077,213 Wave driven generator20030091393 Wave power machine 20030110767 Method and installation ofpower generation by ocean wave 20070164569 Ocean energy harvestingsystem 20070164568 Wave energy recovery system 20070132246 Wave energyconversion system 20050099010 Wave energy conversion system 20070180823Wave energy device

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH & DEVELOPMENT

Not Applicable. No others have rights to this patent.

BACKGROUND OF THE INVENTION

Populations grow exponentially, demand for energy is escalating, andpolitical tensions over hydrocarbons are increasing to say the least. Inlight of these issues the U.S. Department of Energy continues to placerenewable energies as a focal point to their program.

When one looks across an open ocean and views the large rolling wavesthe energy is glaringly obvious. Winds travel for hundreds of miles andbeautifully store and compact their energy into waves. The magnitude ofenergy and density of energy in ocean waves is fairly easy tocomprehend. After all, only waves can pitch and roll ships weighingthousands of tons.

To be cost-effective and viable, a wave energy device must be verysimple. It must also be strong to survive punishing ocean environments.Last but not least, it must avoid sophisticated components and have anycritical components protected from the harsh oceanic environment.Simplicity in design ensures low capital investment, low operatingcosts, low maintenance costs, and low energy production costs. Ideally,a wave energy system should be complete and demonstrateinterconnectivity. An individual device should not require individualmooring systems and individual subsea electric cables to shore. Devicesshould float on the water surface to extract maximum wave energy andeither be capable of withstanding storm events, be towed away when thelargest of storms arise, or temporarily sink below water level untilstorms pass.

Upon review of existing patents one will find that most have addressedonly a few of the challenging design requirements mentioned above. Manywave energy patents that have avoided or eliminated the use of one-wayclutches have not sufficiently described how they work and how theywould actually be built. A patent specification must enable any personskilled in the art or science to which the invention pertains to makeand use the same”. Without sufficient descriptions a patent can bedeemed invalid. Without addressing all of the challenging designrequirements an wave energy device cannot cost-effectively and reliablydeliver power. The novel invention presented herein overcomes the abovechallenges. Particular features not found in prior patent applicationsmake this invention fully viable, useful, and beneficial.

BRIEF SUMMARY OF THE INVENTION

The purpose of this invention is to efficiently and cost effectivelytransform water wave energy into useful electrical energy with little orno environmental impact. There are numerous advantages of thisparticular invention in comparison with prior art.

Maximum available wave power, not partial available power, is extractedby this device and it is extracted on both up and down strokes. Torquearms, acting as levers, add mechanical advantage for power output. Therefined design ensures that capital costs will be very low andreliability will be extremely high. Critical components are 100%protected from oceanic spray keeping maintenance costs negligible. Noreversing gears are utilized and slightly higher gearing ratios are usedfor significant benefits. The efficiency losses associated with reducinggears is completely eliminated. Reversing gear systems have generatorsthat spin too slowly and are not of large enough diameter. Thus, thesegenerators become too heavy and expensive. Heavy generators inhibit awave energy device from harnessing energy because the device cannotproperly maintain rhythm or resonance with wave motions. Standardgearboxes can and should be utilized instead of reversing gear systemsand such gearboxes can come from many suppliers at fairly low prices.

The use of one-way clutches in wave energy devices presents additionalefficiency losses and higher costs. It is better to simply reduce themass moment of inertia of the gearing and generator so that both gearboxand generator can spin in both directions as waves rise and fall.Multiple hinge points make the device stronger in rough seas and/orquartering seas, enables system redundancy, and enables gearboxes andgenerators with smaller diameters and lower mass moments of inertia. Incombination with reduced mass moments of inertia these wave energydevices should have equipment that accommodates the changing directionof a generator's current flow as waves change from up to down stroke. Inessence, sensors would recognize when waves change from up to downmotion or when a generator's current direction changes. At these momentsthe electrical paths would be switched or flip-flopped so that agenerator's current is ultimately heading in the preferred direction.Modern electrical equipment can have milli-second response times. In oneembodiment, as shown in FIG. 3, the electrical lines are switched at thechanging of wave strokes so that the outflow paths remain unchanged.

Buoys can be flooded and the device temporarily submerged below waterlevel. A system for interconnecting energy transformation devices isincluded herein. Interconnectivity creates a truly complete system thateliminates the need for many individual mooring lines, eliminates aconsiderable amount of electrical cable, and it allows many of units tobe towed via a single tugboat. Towing of many units is desirable sincemany units could potentially be installed or removed all at once. Masstowing also enables production-line maintenance at shoreline.Assembly-line maintenance at shoreline is far less expensive and saferthan maintenance or repair performed offshore. In essence, while manyother arrays are generating power just one array at a time can bebrought in for service.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 is a plan and side view of a preferred embodiment of theinvention where reversing gears and one-way clutches have beeneliminated from the design.

FIG. 2 is a plan and side view of a preferred embodiment of theinvention where reversing gears, one-way clutches and gearboxes havebeen eliminated from the design.

FIG. 3 is a drawing of a switch that could accommodate the changing ofwave up/down stroke.

FIG. 4 is an isometric view of a two buoy version of the device withmany hinge points.

FIG. 5 is a plan view of many devices connected together with aninterconnectivity and mooring system.

DESCRIPTION OF THE PREFERRED EMBODIMENT

The invention can be designed and scaled for any size waves. A preferredembodiment would primarily be constructed of steel or other suitablemarine materials. Components of the device include two or more buoys (1)connected by torque arms (2) whereby a pivoting motion is permitted athinge points (3) that have bushing or bearings. The buoy movementsgenerate torque which drive one or more gearboxes (4) which in turnsdrives one or more generators (5) at higher speeds for electricaloutput.

The complex transmission system described in U.S. Pat. No. 7,315,092 istoo customized and expensive, reversing gears are not necessary, andreversing gears present unnecessary efficiency losses. Most importantly,the electrical load, or the amount a wave energy device is trying topower, can be controlled such that the moment of inertia of gearboxesand generators can be consumed before a wave reverses direction. Forexample, electrical load can be electronically increased just as a waveturns from going up to going downward which would stop the gearboxes andgenerators. Thus, one-way clutches are not necessary. When a gearboxwith dual output shafts is used there can be two generators which asshown at the bottom of the device depicted in FIG. 1. These twogenerators are labelled as generator (6) and generator (7). This dualgenerator configuration can inherently reduce the mass moment of inertiaof the system since two generators with smaller diameters can have lessmoment of inertia than one generator of larger size and diameter.Another problem associated with the transmission system described inU.S. Pat. No. 7,315,092 is that it does not permit a high enoughrotational speed for the generators to work efficiently. As a result,the U.S. Pat. No. 7,315,092 has generators that are too large, tooexpensive, too heavy, and they therefore inhibit the device's ability tomove with the waves and generate power. This is why gearboxes withhigher gearing ratios have been used in this invention.

Although it is desirable that wave energy devices be relativelyinvisible on the horizon, corners/edges of arrays (many units linkedtogether) will likely be marked with traditional lighted buoys. Thiswill ensure that they are visible from ships at night and in fog.

All critical components are enclosed and protected since the buoys (1)themselves function as protective shells. The only exposed moving jointsare the bushings/bearings (8) that are properly designed for submersionin salt water. Common propeller shafts of ships have very similarwatertight bearings and seals. If desired, and since the torque arms donot rotate in excessive angles, a sleeve (9) can be installed to coverany bushings/bearings from salt water contact. This inventiondeliberately raises the elevation of the pivot points (10) to above meanwaterline. Propeller shaft seals are designed to be used fullyunderwater but leakage is far less likely with the pivot points, sealsand sleeves/boots elevated above waterline. Universal joints or flexjoints (11) may be used to ensure that only pure torque entersgearboxes. Nylatron, plastic, or other pad materials (12) can be used atpivot points to ensure the torque arms do not rub or contact the buoy.

In the preferred embodiment the buoys (1) are flattened but in otherembodiments the buoys could have a wide range of volumetric shapes.Flattened buoys or buoys enable immediate response to wave motions.Buoys are constructed of thick materials or deliberately weighted inthis embodiment such that they float at about mid level. Weights couldbe made of concrete, other solid materials, or liquid materials.Buoyancy provides an upward force while weight provides a downwardforce, both of which generate useful torque. As a result, both upwardand downward buoy motions result in torque that ultimately drivesgenerators (5). Splitting this torque relatively evenly, vs. twice thetorque on just up or down strokes, reduces the cost of the drive train(gearboxes, generators, etc). Without thick buoy plating or weights (13)the resistance of generators (5) and gears would likely cause buoys to“stick” in an upward position upon the first wave crest. At a minimum,the downward movement of buoys would likely be delayed.

As mentioned previously, buoys are connected via torque arms (2). Torquearms may have the capability of automatically extending or retractingthemselves via auto-lengthening mechanisms. Auto-lengthening mechanismscan accommodate varying wavelengths as sea conditions change on anygiven day. Arm length adjustability increases energy production sincedistances between outer buoys can better match wavelengths on a givenday for optimized power output. In a preferred embodiment, one waveenergy device within a large array could measure wave heights and waveperiods. A computer program could then estimate average wavelengths fromthe recorded data and instruct all torque arms within that array tolengthen or shorten accordingly. In the preferred embodiment, theauto-lengthening mechanisms are actuated electromechanically but theycould also be actuated via hydraulics or other means. Auto-lengtheningmechanisms, like the primary bearings, can be protected from saltwatercontact by waterproof sleeves.

With wave movements the motion of one buoy relative to the other buoy orbuoys creates extremely high torque. Very high torque is a result of thelarge displacement of a buoy (1) coupled with the torque arm lengthswhether the arms are long or short. The high torque is next directlytransferred via the torque arms (2) to a shaft which rotates a gearbox(4). Note that gears, chains and sprockets, or other means can serve totransfer torque to one or more generators.

Similar to arrays of offshore wind turbines, electrical processingequipment can take the electrical output of each generator, process andcombine it at a central electrical processing station, and send it toshore via a single subsea cable, batteries, compressed air, or othermeans. In a one embodiment a central electrical processing station isenclosed within a windowless room and located on a barge near the centerof an array. The windowless room could be climate controlled anddehumidified to better protect the equipment within the electricalprocessing station. Alternatively, the central electrical processingstation could be located in a subsea pod.

Components of energy transformation devices that are exposed to theelements, which include buoys and torque arms, can be structurallydesigned for storm and hurricane forces. Offshore oil platforms havesimilar pontoons and tubulars that are designed for such storms. Manytorque arms can be used and they can be laterally braced and/or trussed(14) as well as vertically braced and/or trussed. In a preferredembodiment, if excessively large waves were encountered, the gearboxcould automatically disengage via a clutch. Slip clutches (15) such asthose constructed of spring loaded frictional discs can be installed toensure that gearboxes and all remaining drive train machinery can neverbe over-loaded. This disengagement feature permits wave energy devicesto accommodate excessively dynamic conditions without any damagingeffects to internal components.

In rough seas, wave energy devices would have a natural tendency tocollide with one another within their arrays. Note that any point on anindividual device will move through all six degrees of translation androtation within a wave cycle. Consequently, there is no single point onan energy transformation device that can be “grabbed” or “held” rigidlyin an attempt to interconnect them. FIG. 5 shows flexibleinterconnection lines (15) connected between devices with mooring lines(16) and anchors (17) at the ends of arrays to keeps lines taught andall devices from contacting one another. Items 15, 16, and 17 togethercreate an interconnect system.

Wave energy devices of this type with just two hinge points, asdescribed in U.S. Pat. No. 7,315,092, are not likely to be structurallystrong enough to handle waves coming from diagonal direction or“quartering seas” as this is sometimes called. Devices with few hingepoints typically have fewer gearboxes and generators with much largermass moments of inertia. Many torque arms and hinge points are shown inFIG. 4. Many hinge points not only makes the device stronger in roughseas but it enables many gearboxes and generators, a lower total massmoment of inertia in the machinery, system redundancy, and smaller gearswhich can reduce costs. Smaller gearboxes and gears is just one way thatmoment of inertia in the drive trains can be reduced which enables lowerenergy losses. Rotation of generators directly and without gearboxes isanother way to reduce inherent energy losses and improve efficiency.With the advent of slow rpm generators, annular generators (18), anddirect drive generators we can now eliminate gearboxes in wave energydevices. Previous wave energy devices have not been able to successfullyprove the operation of, and thus patent, a truly viable wave energydevice without gearboxes. This is now possible when annular or directdrive generators are used. An electronic means by which to controlelectrical load (19) can be installed to reduce if not eliminate themass moment of inertia of machinery items between wave up and downstrokes. Switches (20) or other means by which to ensure that allcurrent goes to grid in the desired direction or fashion can also beadded so that one-way clutches are not necessary. In essence, theseswitches or other means make the reversing of up/down wave directionirrelevant. A means by which to control electrical load, or any othermeans by which to control the flexibility of the device about hingepoints, further enables the device to stay in sync with wave motionswhich can improve if not optimize power output.

Patent applications must sufficiently describe a system for the patentto valid. Furthermore, inventions are novel, beneficial, and patentablewhen they greatly simplify existing inventions and improve efficiency.Adding an item to an existing invention could be consideredinfringement. Patent laws state that subtracting items, however, canresult in new patents. In summary, inventions that result in fewercomponents, simplified systems, and higher efficiencies are patentable.This is the case in this invention.

1. A device for transforming the energy of water waves into useableenergy comprising two or more buoys, and structural members connectingsaid buoys, at least two hinge points, whereby motions of said buoysrelative to one another generates torque, one or more shafts or othermeans by which to transfer torque connected to one or more generators,and a means by which to ensure that one or more generator outputcurrents flow in a single useful direction despite the reversing ofgenerator rotation.
 2. The device of claim 1 with one or more slipclutches or other means by which to automatically disengage torque atappropriate times.
 3. The device of claim 1 with a means by which tocontrol electrical load or otherwise control the flexibility of thedevice at hinge points.
 4. The device of claim 1 whereby one or moretransmissions or gearboxes are added which increase the speed of one ormore generators.
 5. The device of claim 1 whereby one or more structuralmembers are made automatically adjustable in length resulting inimproved energy production.
 6. The device of claim 1 whereby aninterconnect system is included.
 7. The device of claim 1 whereby one ormore buoys are sufficiently weighted resulting in useful torque duringboth upward and downward buoy motions.
 8. The device of claim 1 with ameans by which to temporarily submerge the device when environmentalconditions are deemed too onerous.
 9. A device for transforming theenergy of water waves into useable energy comprising two or more buoys,and structural members connecting said buoys, at least three hingepoints, whereby motions of said buoys relative to one another generatestorque, one or more shafts or other means by which to transfer torqueconnected to one or more generators, a means by which to ensure that oneor more generator output currents flow in a single useful directiondespite the reversing of generator rotation, and a means by which tocontrol electrical load or otherwise control the flexibility of thedevice at hinge points.
 10. The device of claim 9 with one or more slipclutches or other means by which to automatically disengage torque atappropriate times.
 11. The device of claim 9 whereby one or moretransmissions or gearboxes are added which significantly increase thespeed of one or more generators.
 12. The device of claim 9 whereby oneor more structural members are made automatically adjustable in lengthresulting in improved energy production.
 13. The device of claim 9whereby an interconnect system is included.
 14. The device of claim 9whereby one or more buoys are sufficiently weighted resulting in usefultorque during both upward and downward buoy motions.
 15. The device ofclaim 9 with a means by which to temporarily submerge the device whenenvironmental conditions are deemed too onerous.
 16. A device fortransforming the energy of water waves into useable energy comprisingtwo or more buoys, and structural members connecting said buoys, threeor more hinge points that are elevated above mean water level, wherebymotions of said buoys relative to one another generates torque, one ormore shafts or other means by which to transfer torque connected to oneor more generators, a means by which to protect one or more shaftlocations from water penetration, a means by which to ensure that one ormore generator output currents flow in a single useful direction despitethe reversing of generator rotation, and a means by which to controlelectrical load or otherwise control the flexibility of the device athinge points.
 17. The device of claim 16 with one or more slip clutchesor other means by which to automatically disengage torque at appropriatetimes.
 18. The device of claim 16 whereby one or more transmissions orgearboxes are added which significantly increase the speed of one ormore generators.
 19. The device of claim 16 whereby one or morestructural members are made automatically adjustable in length resultingin improved energy production.
 20. The device of claim 16 whereby aninterconnect system is included.
 21. The device of claim 16 whereby oneor more buoys are sufficiently weighted resulting in useful torqueduring both upward and downward buoy motions.
 22. The device of claim 16with a means by which to temporarily submerge the device whenenvironmental conditions are deemed too onerous.